A lot of season one runs fit this criteria for me.
"The Stone Marker of Leif Erickson" though has to be the most forgettable run in my case. There is nothing even slightly memorable about that run. The only thing that sticks out is Keeleys screams in the Observatory. Other than that, nothing exciting happens during that run.
"The Treasure Map of Jean Lafitte"was pretty forgettable also, and I don't remember much details from this run. Its so boring and hard to watch that I never go back and rewatch it.
"The Diary of Dr. Livingstone" win doesn't seem to exist half of the time either when trying to remember wins of the show. It was just a forgettable run with slow and average players. Even with the number of rooms Brett entered, I never really got excited for this run.
"The Mystical Spellbook of the Imperial Wizard" was one of the runs I forgot for the longest time. When I came back to this forum a year ago after a two year break from legends, it took me two months to realize this episode even existed. It didn't help that Nick GAS never aired this episode at all that much either. Also, no one even talks about this run, so its not one that ever sticks out.
And I second "The Lion-Slashed Jacket of Sacagawea". That is another run that is hard for me to draw details from like the temple guard placement and the path that the team chose. Most runs I can remember this information, but I just can't seem for the life of me remember any of these details.